1. Field of the Invention
This invention relates to a ceramic ornament, and particularly to a method of making a ceramic ornament having short undercuts on a surface thereof.
2. Description of the Prior Art
To mold a conventional ceramic ornament, a primary clay body is usually used for making a production mold assembly by means of plaster. After slip is poured into the plaster mold assembly, the plaster mold assembly will absorb the moisture in the slip; as soon as the clay body has a suitable thickness, the slip is poured out. After the clay body is dried to a condition of demolding, the clay body is removed from the plaster mold assembly to be formed into a complete ceramic ornament. The clay body is then fired to form a plain clay body. When plaster is used as a production mold assembly, an undercut part in the clay body should be avoided, and the split line of the mold has to be set exactly. Sometimes several split lines of the mold may be required so as to avoid an undercut. Further, in the case of the surface having dense short undercuts, the conventional plaster mold assembly cannot be used for mass production.
In the event the surface of a clay body has dense short undercuts, the mold assembly must be made of silicone. The surface of the clay body is coated with a thin layer of silicone to prevent the generation of bubbles. Then, the clay body is put in a suitable container, positioned therein properly, and a large amount of silicone slip is poured therein to eliminate the bubbles by means of a vacuum process. For the demolding operation, a suitable opening is cut after the silicone slip has set, and the primary clay body is taken out. Then, a silicone mold assembly is finished. The silicone mold assembly may be poured with a plaster slip or a resin slip. As soon as the slip has set, the body is removed from the mold and an ornament made of plaster or resin is finished. When using the silicone mold assembly, the slip can set, such as a plaster slip, which can be in dried condition permanently, i.e., to become hardened with moisture. When using resin, a hardening agent should be used and blended with the primary substance in order to have a hardening reaction.